Almost any kind of information can be represented digitally as a computer file. Once so represented, this information becomes extremely easy to duplicate and transmit. This can be perceived as problematic for the owners of the information, who may wish to charge copying or licensing fees for the use of the material represented.
In the case that the digital document is a piece of software, prior approaches to the problem have often depended on modifications to the operation of the software itself that check for some evidence that the terms of the license have been met. Prior approaches of more general applicability attempt to restrict access to digital documents through encryption or the imposition of access controls in the computer systems on which they are represented. These solutions share the failing that they either rely on specialized hardware or are easy to circumvent by removing the checks or re-saving the unprotected document after access has been granted. Furthermore, once these measures have been so circumvented, or if unprotected versions of documents are available from other sources, all protection for the document is lost: further unprotected versions of documents may now be duplicated and transmitted with ease. All such solutions also pose a significant inconvenience to the legitimate user of the document, since either the process of moving the document onto their system or of using it thereafter involves the extra step of establishing the right to do so, through the presentation of physical evidence of that right, and in some cases the special configuration of access management facilities.
The above difficulties and inconveniences generally arise from the presumption of an adversarial relationship between the producers and the users of digitally represented documents.
These problems are exacerbated by the fact that digital documents may be a priori hard to examine: unless their format is known, the steps that must be taken to use them are not apparent. Even when the format is known, the means to interpret it may not be available. Thus, even when digital documents are nominally self-identifying (containing embedded bibliographic and licensing information, for example), it may not be feasible to read this information. Furthermore, the format of a document may simply lack a provision for the inclusion of such identifying data. Thus, even when the receiver of a digitally represented document wishes to comply with the conditions associated with its possession or use, it may not be feasible, in the current art, to determine what these conditions are.
These several difficulties are especially pronounced when the person responsible for assuring compliance with licenses, the person responsible for acquiring digital documents, and the person using them, are distinct, as is typically the case in networked computing environments. Fortunately, in such environments there is typically no such need to assume an adversarial relationship between document producers and the person charged with assuring compliance with licenses.
Thus there is a clear need for a system that informs users of the conditions associated with the duplication or use of a digital document that does not rely on the user having specialized hardware or on the particular representation of the document or the means by which it is usually processed. It can presume upon the co-operation of its user, if not of that of all users of the computing system on which it is employed.